Oregon pulled out all the stops Tuesday, in a chance to avenge last month's sweep in Corvallis.

The Ducks used shutdown relievers Garrett Cleavinger and Jake Reed for 3 2/3 innings, preserving a tie score in the nonconference game at PK Park. They sent pinch runner Desmond Santos home from second base on a single to left field in the eighth, though there was one out; Santos was thrown out by OSU all-American Michael Conforto. And in the 12th inning, with OSU having taken a lead, the Ducks bunted a runner to second, playing for the tying run to extend the game.

Ultimately it was all for naught, as Oregon State beat Oregon for the fourth time this season, 4-3. The Beavers denied the Ducks in two late-inning comeback attempts to open their conference series in late April, then won a one-sided Sunday finale.

"We feel like we played better" on Tuesday, UO third baseman Mitchell Tolman said. "Late in the game we kind of got away from having good approaches at the plate. Our pitchers picked us up a lot tonight. Frustrating loss."

The Ducks (34-14) saw their 16-game home win streak end, losing at PK Park for the first time since March 14. They play at Portland on Wednesday at 3 p.m., then fly to Arizona State for a three-game series beginning Friday.

Tuesday's game began in somewhat expected form, given that it was a midweek nonleague matchup between two Pac-12 rivals. Neither started one of its usual starting pitchers, with Stephen Nogosek striking out six and allowing one run in three innings for the Ducks.

The score was 3-3 through four innings, the Beavers capitalizing on some wildness by Oregon's first reliever, Cooper Stiles, and the Ducks taking advantage of three OSU errors. But then play tightened up.

Stiles was relieved by Darrell Hunter in the sixth with two on and two out. With Conforto waiting in the on-deck circle, Hunter went 3-2 on OSU's Andy Peterson; a walk would have loaded the bases and given Conforto a chance for his second grand slam in two games at PK Park going back to last season, but Hunter coaxed a flyout to end the inning.

Hunter was in turn picked up by Cleavinger, who came on with two on and one out in the seventh and retired the side. Cleavinger then pitched a clean eighth inning, redemption after he took the loss in Corvallis on April 26.

"(The Beavers) were giving him a little bit of an earful," UO coach George Horton said. "He kept his mouth shut and pitched really good. That's how you respond to something like that."

Cleavinger might have been Tuesday's winning pitcher had Santos crossed safely in the bottom of the eighth. Shaun Chase continued his torrid hitting with a one-out double, and Santos replaced him as a pinch runner. Josh Graham followed with a single through the left side of the infield; Santos hesitated to make sure the ball got through and then got on his horse, but was thrown out at home by Conforto.

"It was a bang-banger," Horton said. "We pinch-ran Desmond for Shaun for that reason. Even though the ball was in front of him, I thought he got a reasonably good jump. But Conforto can beat you in a lot of ways."

The Ducks threw out runners at home as well, in both the third and fourth innings.

Oregon State won it in the 12th by stringing together a single, a hit batter, a walk and a sacrifice fly off Jordan Spencer. Aaron Payne led off the bottom of the inning with a walk and was bunted to second, but the Ducks couldn't push him across.

The use of six pitchers Tuesday leaves the Ducks' staff perilously thin entering the game at Portland. Left-hander Porter Clayton is scheduled to start, with righties Derek Smith and Trent Paddon also probably factoring into the team's plans.

"We're going to have to have some guys step up and do some pitching they haven't done so far," Horton said, adding as well that "we're going to have to score some runs probably."